I want to be able to get the result of a query stored in a column, parametrized by value in another one. Model is more relational ( queries are in a 1--n linked table ), but to keep it simple :
value | query
-------------
25 | SELECT id, name FROM courses
12 | SELECT id, name FROM countries
I want to be able to get the results of the queries, so something like
SELECT EXEC(query + ' WHERE id = ' + value) FROM table
I would like to do without the application side to do that.
Is it possible ?
PS: the risk of SQL Injection does not come into play, it's already managed.
One posible approach is to generate and execute a dynamic statement for all your possible SELECT statements.
Table:
CREATE TABLE #Statements (
[value] int,
[query] nvarchar(max)
)
INSERT INTO #Statements
([value], [query])
VALUES
(25, N'SELECT id, name FROM courses'),
(12, N'SELECT id, name FROM countries')
T-SQL:
DECLARE #stm nvarchar(max) = N''
SELECT #stm = (
SELECT
CONCAT(
[query],
N' WHERE id = ',
[value],
N'; '
)
FROM #Statements
FOR XML PATH('')
)
PRINT #stm
EXEC sp_executesql #stm
Generated statements:
SELECT id, name FROM courses WHERE id = 25;
SELECT id, name FROM countries WHERE id = 12;
If you want to retrieve the results from all your statements into a single result set and if columns id and name have compatible data types, you can execute next statement (with possible CONVERT calls):
DECLARE #stm nvarchar(max) = N''
SELECT #stm = STUFF(
(
SELECT
CONCAT(
N'UNION ALL ',
[query],
N' WHERE id = ',
[value],
N' '
)
FROM #Statements
FOR XML PATH('')
),
1, 10, N'')
PRINT #stm
EXEC sp_executesql #stm
Related
I'm trying to build a stored procedure that will query multiple database depending on the databases required.
For example:
SP_Users takes a list of #DATABASES as parameters.
For each database it needs to run the same query and union the results together.
I believe a CTE could be my best bet so I have something like this at the moment.
SET #DATABASES = 'DB_1, DB_2' -- Two databases in a string listed
-- I have a split string function that will extract each database
SET #CURRENT_DB = 'DB_1'
WITH UsersCTE (Name, Email)
AS (SELECT Name, Email
FROM [#CURRENT_DB].[dbo].Users),
SELECT #DATABASE as DB, Name, Email
FROM UsersCTE
What I don't want to do is hard code the databases in the query. The steps I image are:
Split the parameter #DATABASES to extract and set the #CURRENT_DB Variable
Iterate through the query with a Recursive CTE until all the #DATABASES have been processed
Union all results together and return the data.
Not sure if this is the right approach to tackling this problem.
Using #databases:
As mentioned in the comments to your question, variables cant be used to dynamically select a database. Dynamic sql is indicated. You can start by building your template sql statement:
declare #sql nvarchar(max) =
'union all ' +
'select ''#db'' as db, name, email ' +
'from [#db].dbo.users ';
Since you have sql server 2016, you can split using the string_split function, with your #databases variable as input. This will result in a table with 'value' as the column name, which holds the database names.
Use the replace function to replace #db in the template with value. This will result in one sql statement for each database you passed into #databases. Then, concatenate the statements back together. Unfortunately, in version 2016, there's no built in function to do that. So we have to use the famous for xml trick to join the statements, then we use .value to convert it to a string, and finally we use stuff to get rid of the leading union all statement.
Take the results of the concatenated output, and overwrite the #sql variable. It is ready to go at this point, so execute it.
I do all that is described in this code:
declare #databases nvarchar(max) = 'db_1,db_2';
set #sql = stuff(
(
select replace(#sql, '#db', value)
from string_split(#databases, ',')
for xml path(''), type
).value('.[1]', 'nvarchar(max)')
, 1, 9, '');
exec(#sql);
Untested, of course, but if you print instead of execute, it seems to give the proper sql statement for your needs.
Using msForEachDB:
Now, if you didn't want to have to know which databases had 'users', such as if you're in an environment where you have a different database for every client, you can use sp_msForEachDb and check the structure first to make sure it has a 'users' table with 'name' and 'email' columns. If so, execute the appropriate statement. If not, execute a dummy statement. I won't describe this one, I'll just give the code:
declare #aggregator table (
db sysname,
name int,
email nvarchar(255)
);
insert #aggregator
exec sp_msforeachdb '
declare #sql nvarchar(max) = ''select db = '''''''', name = '''''''', email = '''''''' where 1 = 2'';
select #sql = ''select db = ''''?'''', name, email from ['' + table_catalog + ''].dbo.users''
from [?].information_schema.columns
where table_schema = ''dbo''
and table_name = ''users''
and column_name in (''name'', ''email'')
group by table_catalog
having count(*) = 2
exec (#sql);
';
select *
from #aggregator
I took the valid advice from others here and went with this which works great for what I need:
I decided to use a loop to build the query up. Hope this helps someone else looking to do something similar.
CREATE PROCEDURE [dbo].[SP_Users](
#DATABASES VARCHAR(MAX) = NULL,
#PARAM1 VARCHAR(250),
#PARAM2 VARCHAR(250)
)
BEGIN
SET NOCOUNT ON;
--Local variables
DECLARE
#COUNTER INT = 0,
#SQL NVARCHAR(MAX) = '',
#CURRENTDB VARCHAR(50) = NULL,
#MAX INT = 0,
#ERRORMSG VARCHAR(MAX)
--Check we have databases entered
IF #DATABASES IS NULL
BEGIN
RAISERROR('ERROR: No Databases Provided,
Please Provide a list of databases to execute procedure. See stored procedure:
[SP_Users]', 16, 1)
RETURN
END
-- SET Number of iterations based on number of returned databases
SET #MAX = (SELECT COUNT(*) FROM
(SELECT ROW_NUMBER() OVER (ORDER BY i.value) AS RowNumber, i.value
FROM dbo.udf_SplitVariable(#DATABASES, ',') AS i)X)
-- Build SQL Statement
WHILE #COUNTER < #MAX
BEGIN
--Set the current database
SET #CURRENTDB = (SELECT X.Value FROM
(SELECT ROW_NUMBER() OVER (ORDER BY i.value) AS RowNumber, i.value
FROM dbo.udf_SplitVariable(#DATABASES, ',') AS i
ORDER BY RowNumber OFFSET #COUNTER
ROWS FETCH NEXT 1 ROWS ONLY) X);
SET #SQL = #SQL + N'
(
SELECT Name, Email
FROM [' + #CURRENTDB + '].[dbo].Users
WHERE
(Name = #PARAM1 OR #PARAM1 IS NULL)
(Email = #PARAM2 OR #PARAM2 IS NULL)
) '
+ N' UNION ALL '
END
PRINT #CURRENTDB
PRINT #SQL
SET #COUNTER = #COUNTER + 1
END
-- remove last N' UNION ALL '
IF LEN(#SQL) > 11
SET #SQL = LEFT(#SQL, LEN(#SQL) - 11)
EXEC sp_executesql #SQL, N'#CURRENTDB VARCHAR(50),
#PARAM1 VARCHAR(250),
#PARAM2 VARCHAR(250)',
#CURRENTDB,
#PARAM1 ,
#PARAM2
END
Split Variable Function
CREATE FUNCTION [dbo].[udf_SplitVariable]
(
#List varchar(8000),
#SplitOn varchar(5) = ','
)
RETURNS #RtnValue TABLE
(
Id INT IDENTITY(1,1),
Value VARCHAR(8000)
)
AS
BEGIN
--Account for ticks
SET #List = (REPLACE(#List, '''', ''))
--Account for 'emptynull'
IF LTRIM(RTRIM(#List)) = 'emptynull'
BEGIN
SET #List = ''
END
--Loop through all of the items in the string and add records for each item
WHILE (CHARINDEX(#SplitOn,#List)>0)
BEGIN
INSERT INTO #RtnValue (value)
SELECT Value = LTRIM(RTRIM(SUBSTRING(#List, 1, CHARINDEX(#SplitOn, #List)-1)))
SET #List = SUBSTRING(#List, CHARINDEX(#SplitOn,#List) + LEN(#SplitOn), LEN(#List))
END
INSERT INTO #RtnValue (Value)
SELECT Value = LTRIM(RTRIM(#List))
RETURN
END
I am developing a custom application using CodeIgniter and MSSQL Server. Here i am using stored procedures.
Now i am wondering to implement codeigniter query type functionality where i can create a universal stored procedure in SQL Server and at the time of using i can pass tablename, array of fields and values.
It can work for both insert and update.
Something like we do in CodeIgniter to execute the query,
$data = array('fieldname1' => 'value1',
'fieldname2' => 'value2');
$this->db->insert($tablename,$data);
Just like this if we can pass the table name and array of the data to stored procedure and stored procedure automatically execute it.
If this can be done, it can save lots n lots of man hours. If anyone have already done i will be very much happy to see the solution.
You need to make string very specific in this case.
Figure out your table name, Column name, Column values for insert. For update 2 more parameters are required Id column name and its value.
GO
---- exec InsertUpdate 'tablename', 'col1, col2, col3', 'val1, val2, val3', 'idcol', 'idval'
GO
Create proc InsertUpdate
( #TableName nvarchar(500),
#ColName nvarchar(max),
#ColValues nvarchar(max),
#IDColName nvarchar(100) = '', --- for update only otherwise null
#IdColValue nvarchar(Max) = '' --- for update only otherwise null
)
As
Begin
declare #Query nvarchar(max)
if (#IdColValue = '')
Begin
set #Query = ' Insert into ' + #TableName + ' (' + #ColName + ') values (' + #ColValues + ')'
End
Else
Begin
;with CtColumn as (
select ROW_NUMBER() over (order by (select 1000)) as Slno, * from Split(#ColName,',') )
, CtValue as (
select ROW_NUMBER() over (order by (select 1000)) as Slno, * from Split(#ColValues, ','))
, CTFinal as (
select CCOl.Slno, CCOl.Items as ColName, CVal.Items as ColValue from CtColumn as CCOl inner join CtValue as CVal on CCOl.Slno=CVal.Slno )
select #Query = 'update ' + #TableName + ' set ' +
stuff ( (select ',' + ColName + '=' + ColValue from CTFinal for xml path ('')) ,1,1,'') +
' where ' + #IDColName + '=' + #IdColValue
End
exec sp_executesql #Query
End
Go
I have to write update using dynamic sql becaus i know only name of column that I want to update and names of columns which I will use to join tables in my update. But I don't know the numbers of tables and names. Names of tables I will get in parameter of my procedure in this way
declare #Tables = N'Customer,Employee,Owner'
So I want to have update like this:
update t
set [Status] = 100
from
TemporaryTable t
left join Customer t1 on t1.RecordId = t.RecordId
left join Employee t2 on t2.RecordId = t.RecordId
left join Owner t3 on t3.RecordId =t.RecordId
where
t1.RecordId is null
and t2.RecordId is NULL
and t3.RecordId is null
I know that each table will have column RecordId and want to left join this tables to my TemporaryTable on this column but I don't know the names and numbers of tables. For example I will have one, two, or ten tables with different names. I know that this tables names will be save in parameter #Tables in that way:
#Tables = N'Customer,Employee,Owner'
There is possilble to write this update in dynamic way?
This is an answer, which helps ... to write update using dynamic sql ... and only shows how to generate a dynamic statement. It's based on string splitting. From SQL Server 2016+ you may use STRING_SPLIT() (because here the order of the substrings is not important). For previous versions you need to find a string splitting function.
T-SQL:
DECLARE #Tables nvarchar(max) = N'Customer,Employee,Owner'
DECLARE #join nvarchar(max) = N''
DECLARE #where nvarchar(max) = N''
DECLARE #stm nvarchar(max) = N''
SELECT
#join = #join + CONCAT(
N' LEFT JOIN ',
QUOTENAME(s.[value]),
N' t',
ROW_NUMBER() OVER (ORDER BY (SELECT 1)),
N' ON t',
ROW_NUMBER() OVER (ORDER BY (SELECT 1)),
N'.RecordId = t.RecordId'
),
#where = #where + CONCAT(
N' AND t',
ROW_NUMBER() OVER (ORDER BY (SELECT 1)),
N'.RecordId is NULL'
)
FROM STRING_SPLIT(#Tables, N',') s
SET #stm = CONCAT(
N'UPDATE t SET [Status] = 100 ',
N'FROM TemporaryTable t',
#join,
N' WHERE ',
STUFF(#where, 1, 5, N'')
)
PRINT #stm
EXEC sp_executesql #stm
Notes:
One note, that I think is important - consider passing tables names using table value type for parameter, not as comma-separated text.
It seems like this will suit your needs, though I don't fully understand what you're trying to do. Here we're constructing the final SQL in two pieces (#s and #where) and then concatenating into the final SQL at the end.
declare #Tables varchar(100) = N'Customer,Employee,Owner'
declare #tablenames table (tablename nvarchar(100))
insert #tablenames (tablename)
select value
from string_split(#Tables, ',');
declare #where varchar(max) = ''
declare #s varchar(max) = '
update t
set [Status] = 100
from TemporaryTable t'
select #s += '
left join ' + tablename + ' on ' + tablename + '.RecordId = t.RecordId'
, #where += case when #where = '' then '' else ' and ' end + tablename + '.RecordId is null
'
from #tablenames
print #s + char(13) + ' where ' + #where
exec( #s + char(13) + ' where ' + #where)
Lets say I have a table that holds a list of other tables
Declare #MyList varchar(max)
#MyList = Select tablename from ListofTables
it brings back a list of 50 tablenames
How can I use that list of tablenames in a single select statement? I was thinking a for loop or something maybe?
For each tablename in #MyList
Select * from tablename
You may try with the next approach:
-- Table
CREATE TABLE #ListOfTables (
[TableName] varchar(max)
)
INSERT INTO #ListOfTables
([TableName])
VALUES
('Table1'),
('Table2'),
('Table3'),
('Table4'),
('Table5'),
('Table6'),
('Table7'),
('Table8'),
('Table9')
-- Statement
DECLARE #stm nvarchar(max)
SET #stm = N''
SELECT #stm = #stm + N'SELECT * FROM ' + QUOTENAME([TableName]) + N'; '
FROM #ListOfTables
/*
-- Or using FOR XML PATH
SELECT #stm = (
SELECT CONCAT(N'SELECT * FROM ', QUOTENAME([TableName]), N'; ')
FROM #ListOfTables
FOR XML PATH('')
)
*/
PRINT #stm
EXEC sp_executesql #stm
i have data in below format. this data is coming through SQL Query.
i want to show it in below format either by query or by rdlc report.
You need to use dynamic SQL to make it.
From your expected result you can try to follow thoes step to make it.
use row_number function make row number by Name, because we need to join base on that row_number.
get the use MAX and MIN to make row number calendar table. from 1 to max(rn). the table can let use outer join
declare a var #tables to make the OUTER JOIN execute SQL (each LEFT JOIN maen a group of Crew#).
declare a var #col to make column, which you want to select (Employee) from each table.
then use execute dynamic execute it.
look like this.
create table T
(
Name varchar(50),
Employee VARCHAR(50)
)
insert into T values ('Crew#1','TR123');
insert into T values ('Crew#1','311');
insert into T values ('Crew#2','DDD');
insert into T values ('Crew#2','12121');
insert into T values ('Crew#1','SDDAS');
insert into T values ('Crew#3','31114312');
insert into T values ('Crew#3','DD14124D');
insert into T values ('Crew#3','1214124121');
insert into T values ('Crew#3','SDD412AS');
DECLARE #tables AS NVARCHAR(MAX),
#query AS NVARCHAR(MAX),
#col AS NVARCHAR(MAX);
SET #tables = STUFF((SELECT distinct ' LEFT JOIN ' + ' (SELECT * FROM CTE WHERE Name = '''+Name+''') '+QUOTENAME(Name)+' on t1.smallRN = '+QUOTENAME(Name)+'.rn'
FROM T
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
SET #col = STUFF((SELECT distinct ', ' + QUOTENAME(Name)+'.Employee as '''+ QUOTENAME(Name) +''''
FROM T
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
SET #col = substring(#col,1, len(#col))
set #query = '
WITH CTE AS (
SELECT *,ROW_NUMBER() OVER(PARTITION BY Name ORDER BY Name) rn
FROM T
),CTE1 AS(
SELECT MIN(rn) smallRN,MAX(rn) bigRN
FROM CTE
UNION ALL
SELECT smallRN+1,bigRN
FROM CTE1
WHERE smallRN < bigRN
)
SELECT '+#col+'
FROM CTE1 t1 ' + #tables
execute(#query)
sqlfiddle
Creatin tbale
First we will create a temp table where we will stock the data that you have and your table
create table #table1
(
[Crew Name] varchar(500) ,
Employee varchar(500)
)
INsert into #table1
values (....)
select * from #table1
Dynamic selection
then we will create a dynamic query to get the columns that we have, that way we can add as much crews as we want,
declare #DynamicPivotQuery as nvarchar(max)
declare #ColumnName as nvarchar(max)
select #ColumnName = ISNULL(#ColumnName +',','') + QUOTENAME([Crew Name])
from (select distinct [Crew Name] from #table1) as Country
set #DynamicPivotQuery = N'select ' +#ColumnName + '
from #table1
Pivot ( MAX(Employee)
FOR [Crew Name] in (' +#ColumnName+')) as Pivoted
'
exec (#DynamicPivotQuery)
this way we will get only the first row for every column
so we have to find a way to aggregate and get the other columns as well just to demonstrate i will union the Mmin also this is where i stoped my testes but you can do more then this with some testes
now the union :
declare #DynamicPivotQuery as nvarchar(max)
declare #ColumnName as nvarchar(max)
select #ColumnName = ISNULL(#ColumnName +',','') + QUOTENAME([Crew Name])
from (select distinct [Crew Name] from #table1) as Country
set #DynamicPivotQuery = N'select ' +#ColumnName + '
from #table1
Pivot ( MAX(Employee)
FOR [Crew Name] in (' +#ColumnName+')) as Pivoted
union
select ' +#ColumnName + '
from #table1
Pivot ( MIN(Employee)
FOR [Crew Name] in (' +#ColumnName+')) as Pivoted
'
exec (#DynamicPivotQuery)
here is the result :
if you follow this way i'm sure that you will find a way to union all the result
You can add this result into a temp table
then add a column which will be a reference into this temp table
then use pivot function
To know more about pivot Visit :
https://msdn.microsoft.com/en-us/azure/data-lake-analytics/u-sql/pivot-and-unpivot-u-sql
you can use also SSIS to a very handy tool and easy to use
Using dynamic PIVOT if you dont have a set Crew columns.
DECLARE #ColumnString VARCHAR(256)
DECLARE #ColumnHeadrer VARCHAR(256)
DECLARE #sql varchar(1000)
CREATE TABLE #ColumnValue
(
Value VARCHAR(500),
ColumnHeader VARCHAR(256)
)
INSERT INTO #ColumnValue (Value, ColumnHeader)
SELECT DISTINCT '[' + CrewName + ']',
'ISNULL(' + CrewName + ','''') AS ' + CrewName
FROM CrewTable
SELECT #ColumnString = COALESCE(#ColumnString + ',', '') + Value,
#ColumnHeadrer = COALESCE(#ColumnHeadrer + ',', '') + ColumnHeader
FROM #ColumnValue
SET #sql =
'
SELECT ' + #ColumnHeadrer + '
FROM
(
SELECT Employee,
CrewName,
ROW_NUMBER() OVER(PARTITION BY CrewName ORDER BY CrewName) AS rnk
FROM CrewTable
) AS P
PIVOT
(
MAX(Employee) FOR [CrewName] IN ('+#ColumnString+')
) AS pv
'
EXEC (#sql)